1. Related Application
This application is a continuation-in-part of U.S. patent application Ser. No. 056,190, filed June 1, 1987, hereby incorporated by reference.
2. Field of the Invention
The invention is related to the synthesis of aromatic propargyl ethers. More particularly, the present invention provides a process for preparing propargyl ethers derived from phenolic compounds.
Propargyl ethers are a class of acetylene-terminated monomers which show great promise for use in the preparation of thermoset resins with excellent properties.
3. Discussion of the Prior Art
U.S. Pat. No. 3,594,175 to Allan S. Hay, discloses producing dipropargyl ethers by reacting dihydric phenol with a propargyl halide in the presence of a base, e.g., alkali metal and alkaline earth metal hydroxides, carbonates, bicarbonates, etc. Because an alkali metal hydroxide reacts with the phenol to produce a salt of the phenol, the preformed alkali metal salt of the dihydric phenol can also be used. The propargyl ether product is purified by recrystallization.
U.S. Pat. No. 4,226,800 to Picklesimer, reports a process wherein a phenolic material is reacted with propargyl bromide in aqueous sodium hydroxide solution. The process suffers from the disadvantage of providing both O-propargylated (desired) and C-propargylated (undesired) materials. For example, bisphenol A is claimed to provide 45.4% yield of the desired bispropargyl ether and 43.6% yield of the undesired C-propargylated bisphenol. Additionally, the process employs rather vigorous conditions, such as reflux conditions of 100.degree. C. for from 1 to 3 hours. A further drawback of the process is that propargyl bromide is used rather than propargyl chloride. The bromide is relatively expensive, inaccessible on a commercial scale, and shock sensitive according to Fire Technology, 5, 100 (1969).
The present invention overcomes deficiencies of the prior art mentioned above, which is hereby incorporated by reference.